Spectrometers are used for many purposes. For example spectrometers are used in the detection of defects in industrial processes, satellite imaging, and laboratory research. However these instruments have typically been too large and too costly for the consumer market.
Spectrometers detect radiation from a sample and process the resulting signal to obtain and present information about the sample that includes spectral, physical and chemical information about the sample. These instruments generally include some type of spectrally selective element to separate wavelengths of radiation received from the sample, and a first-stage optic, such as a lens, to focus or concentrate the radiation onto an imaging array.
The prior spectrometers can be less than ideal in at least some respects. Prior spectrometers having high resolution can be larger than ideal for use in many portable applications. Also, the cost of prior spectrometers can be greater than would be ideal. The prior spectrometers can be somewhat bulky, difficult to transport and the optics can require more alignment than would be ideal in at least some instances.
Although prior spectrometers with decreased size have been proposed, the prior spectrometers having decreased size and optical path length can have less than ideal resolution, sensitivity and less accuracy than would be ideal.
Work in relation to spectrometers suggests that the calibration and measurements with prior spectrometers can be less than ideal in at least some instances. For example, calibration of the spectrometer can be related to accuracy of the measurements. Also, work in relation to spectrometers suggests that positioning of the sample and related measurements can be less than ideal. Also, background noise from sources such as ambient light may affect the measurements. Traditional spectrometers can be large and bulky and approaches to at least some of these problems may not be well suited for use with a hand held portable spectrometer.
Work in relation to spectrometers also suggests that prior methods and apparatus to position a sample with respect to a spectrometer can be less than ideal in at least some instances. For example, variations in distance of the sample from the spectrometer may contribute to variability among results. The orientation of the sample may vary among samples and may contribute to variability among measured spectra. Also, background light and light reflected from surfaces near the sample may affect the measurements.
In light of the above, an improved spectrometer that overcomes at least some of the above mentioned deficiencies of the prior spectrometers would be beneficial. Ideally such a spectrometer would be a compact, provide improved measurements and calibration, be integratable with a consumer device such as a cellular telephone, sufficiently rugged and low in cost to be practical for end-user spectroscopic measurements of items, convenient and convenient to use.